Showing a root is of an equation

Show that 1 is a root of the equation x^3 - 13x + 12 = 0 I can usually do this by dividing the factor in to the equation but I can't seem to work this one out mainly because when I do it I end up having to take x^2 away from 13x which as far as I know you can't do. Any help on this one?

Show that 1 is a root of the equation x^3 - 13x + 12 = 0 I can usually do this by dividing the factor in to the equation but I can't seem to work this one out mainly because when I do it I end up having to take x^2 away from 13x which as far as I know you can't do. Any help on this one?